Welcome to
Day 2
RockOn! 2008
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Announcements:
- Table set up…
- Stay close to your buddy team
- Don’t touch stuff yet
- This is where you will sit for duration of workshop
- Soldering…who has never soldered before
-
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Radiation: Overview
- Radiation is generally viewed as
harmful to space payloads.
- While some projects purposely
expose parts to the saturated
Van Allen belts to investigate
the effects of high energy
particles, some projects must
avoid harmful doses at all costs.
- Sparse data has been collected
from suborbital airspace.
Van Allen Belts: www.nasa.gov
- This payload will allow for a
large collection of data sets.
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Geiger
Counter
Background
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Radiation: Overview
- Radiation is generally viewed as
harmful to space payloads.
- While some projects purposely
expose parts to the saturated
Van Allen belts to investigate
the effects of high energy
particles, some projects must
avoid harmful doses at all costs.
- Sparse data has been collected
from suborbital airspace.
Van Allen Belts: www.nasa.gov
- This payload will allow for a
large collection of data sets.
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Radiation: Effects
- Single event phenomenon
(SEP), burnouts and bit flips
can cause damage to solid
state devices aboard a space
payload.
- An understanding of dose
levels is ideal to plan a
mission to sub-orbital
altitudes, especially with
sensitive optics or
microprocessors.
SEP diagram: www.aero.org/
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Radiation: Effects
- There are three types of radioactive
emissions:
- Alpha - the least penetrating form of
radiation, can be stopped with a piece
of paper or a few inches of air.
- Beta-rays are more penetrating than
alpha-rays
- Gamma-rays are the most penetrating
form of radiation. Often produced in
conjunction with alpha or beta-rays,
they can penetrate several inches of
steel or hundreds of feet in air
Particle comparison:
www.freedomforfissi
on.org.uk
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Radiation: A General Trend
- Radiation levels roughly
double every 5,000 feet in
altitude, so at sea level
dosage will be roughly ½
the level observed in
Denver, Colorado.
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Radiation: A General Trend
- Radiation levels do depend on the level of cosmic radiation,
effective shielding, and any ground or building materials
containing radioactive materials
- In general, at sea level; you should see 12-14 counts per minute
- This device has resolution to 2 μs. Which indicates it cannot
detect particle events closer than 2 μs to each other
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Radiation: A General Trend
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Radiation: Dosage and Limits
- Max dose for occupational workers
(Nuclear Power) 5 Rem/yr (max
exposure to retina). [2]
Shielding can
drastically reduce
the observed dose.
Be sure to wear
safety glasses
when handling the
material.
- Max dose recommended for the
general public 100 mRem from a high
energy source over a short time frame.
[2]
- An average American receives 360
mRem/yr from natural background and
manmade sources. [2]
[2]
http://www.jlab.org/div_dept/train/rad_
guide
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Radiation: Comparisons
- A typical radiation dose from a chest x-ray is about 10 mRem
per x-ray (Gamma exposure) [2]
- Consumer products contain radiation, such as: smoke
detectors, and lantern mantles. This dose is relatively small as
compared to other naturally occurring sources of radiation and
averages 10 mRem/yr (Alpha exposure). [2]
20th Century Fox ©
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Radiation: Conversions
- Generally, 75 counts per minute
(CPM) is equivalent to 1
mRem/hr.
- Therefore, 4,500 CPM is roughly
equivalent to 1 mRem
- A source from a smoke detector
makes up 2.8% of the yearly
average expected dose, which is
.027 mRem/day or .0012
mRem/hr
- These numbers shouldn’t alarm
you, an average person receives
1 mRem per day.
20th Century Fox ©
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Geiger
Counter
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What Are We Building ?
- Basic Geiger Counter
- Audio and Visual Cues
for Radiation Detection
- Can detect Alpha,
Beta, and Gamma
Radiation.
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Prep Step 1: Tool Layout
- Prepare tools for the
construction process.
- Put on your safety
glasses.
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Prep Step 2: Grounding
- Put on a static strap to remain
grounded. Also make sure the strap
is tight across your wrist.
- This will protect any parts from
electro-static discharge (ESD) and its
harmful effects.
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Prep Step 3: Soldering Station
- Turn on the soldering iron
- Set the temperature control on
the soldering iron to a
temperature less than 700 °F
and greater than 450 °F.
- As a general rule use a
temperature in the range
between 550 and 650 degrees
Fahrenheit.
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Prep Step 3: Soldering Station
- Turn on the soldering iron
- Set the temperature control on
the soldering iron to a
temperature less than 700 °F
and greater than 450 °F.
- As a general rule use a
temperature in the range
between 550 and 650 degrees
Fahrenheit.
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Prep Step 3: Soldering Station
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Prep Step 4: Tinning the iron
- Tin the tip of the soldering
iron by melting an inch or so
of solder on the tip.
- The iron will now look shiny
on the tip.
- Then wipe any excess solder
on the golden sponge.
- Now place the iron back into
the holder. Tinning your
soldering iron in this manner
will aid in future soldering.
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Prep Step 4: Tinning the iron (close-up)
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Verify Kit Contents
- Open your kits and verify the contents with the provided
list and visual layout.
- Find the Geiger Mueller (GM) Tube and set it aside in a
safe place.
- You won’t need the GM Tube until the last few steps.
GM TUBE
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Verify Kit Contents: Resistors
-R1 = 4.3KΩ = (YOR)
-R2 = 15KΩ = (BrGrO)
-R3 = 5.6 Ω = (GrBlR)
-R4 = 470KΩ = (YVY)
-R5 = 10 megaΩ = (BrBkBl)
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Verify Kit Contents: Resistors
-R6 = 100KΩ = (BrBkY)
-R7 = 47KΩ = (YVO)
-R8 = 470 Ω = (YVBr)
-R9 = 330 Ω = (OOBr)
-R10 = 1 megaΩ = (BrBkGr)
-R13 = 10 megaΩ = (BrBkBl)
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Verify Kit Contents: Capacitors
- Some capacitors have polarity, while others do not. The
majority of capacitors use during this build are not
polarized.
- *Note these similar capacitors C4=C5 , C2=C8 , and
C3=C10.
- Some capacitors used during this build can carry charge
long after power has been disconnected from the circuit (1530 seconds).
- Use caution especially around the high voltage section of the
circuit to avoid a discharge shock.
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Verify Kit Contents: Capacitors
- C1 = Green Ceramic 0.0047 μF
- C2 = Green Ceramic 0.01 μF
- C3(±) = Yellow Tantalum 100 μF
- C4 = Orange Ceramic 0.01 μF 1 Kv
- C5 = Orange Ceramic 0.01 μF 1 Kv
C1
C2
C3
C4
C5
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Verify Kit Contents: Capacitors
- C6 = Green Ceramic 0.001 μF
- C7 = Green Ceramic or Orange Ceramic 0.047 μF
- C8 = Green Ceramic 0.01 μF
- C10(±) = Yellow Tantalum 100 μF
- C12 = Orange Ceramic 120 pF
- C13 = Blue Ceramic 1.00 μF 50v
C6
C7
C8
C10
C12
C13
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Verify Kit Contents: Diodes
- All diodes in this kit have polarity
- *Note these similar diodes D5=D6 , D2=D3=D9
- D1 = 1N914 =
- D2 = 1N4007 1 Kv =
- D3 = 1N4007 1 Kv =
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Verify Kit Contents: Diodes
- D4 = 1N5271 100 V =
- D5 = 1N5281 200 V =
- D6 = 1N5281 200 V =
- D9= 1N4007 1 Kv =
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Verify Kit Contents: Miscellaneous
Q1 (IRF830)
Q2 (NPN Transistor)
Q3 (7805 Regulator)
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Verify Kit Contents: Miscellaneous
- D7 (Red Led)
-T1 (Mini Step-up Transformer)
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Verify Kit Contents: Miscellaneous
- U1 (16 pin 4049 chip
and socket)
- U2 (8 pin 555 Timer
chip and socket)
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Let’s Start
Building!
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TIPS:
- Make sure the static strap is tight across your wrist at all times.
- DO NOT linger on parts with the soldering iron.
- As a general rule use a 5 second linger time with a 10-20 second
cool time for parts.
- Mount and solder components flush to the board unless
otherwise stated.
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TIPS:
- Make sure the static strap is tight across your wrist at all times.
- DO NOT linger on parts with the soldering iron.
- As a general rule use a 5 second linger time with a 10-20 second
cool time for parts.
- Mount and solder components flush to the board unless
otherwise stated.
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TIPS:
- Use caution when clipping leads
to avoid flinging metal across
the room.
- All soldering must achieve a
good solder filet on the pad as
shown for circuit reliability.
workmanship.
nasa.gov
Example of a good solder filet
- Also clip the leads in this
fashion.
- Bend resistors and diodes using
your plastic tool as shown.
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Let’s Start Building
- The board shall be
oriented in this manner
for the duration of this
kit construction unless
indicated otherwise.
- Raise your hand for
assistance if any issues
arise.
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Step 1: C14
- Mount and solder C14 into the
appropriate place on the PCB.
- **This capacitor is polarized,
note the shorter lead is
negative.**
-
+
- Also, text on the side of the
capacitor indicates the negative
lead.
- This capacitor IS electrolytic,
but it serves as an audio ground
test component only.
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Step 1: C14 (before)
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Step 1: C14 (after)
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Step 2: R6 (100K BrBkY)
- Mount and solder R6 into the
appropriate place on the PCB.
- **This resistor is in a location that
was originally designed for a
capacitor.**
- The PCB design requires the
awkward bending of the resistor.
- Consult the following pictures for
examples of this.
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Step 2: R6 (mounting)
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Step 2: R6 (before)
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Step 2: R6 (after)
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Step 3: 16 pin socket
- Mount and solder the 16 pin socket
to the appropriate location on the
PCB.
Notch
- **This chip socket has a defined
orientation note the notch on the
PCB as well as the socket itself.**
- Match notch to notch to allow the
correct orientation.
- Start by soldering opposite corners
of the socket to mount to the board
for easier soldering. Also ensure
the socket is flush with the board.
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Step 3: 16 pin socket (before)
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Step 3: 16 pin socket (after)
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Step 4: C1 and C2
- Mount and solder C1 and C2 into
the appropriate places on the PCB.
- These capacitors are not polarized,
so the orientation of mounting will
not compromise performance.
C1
C2
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Step 4: C1 and C2 (before)
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Step 4: C1 and C2 (after)
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Step 4: C1 and C2 (after close-up)
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Step 5: D1
- Mount and solder D1 into the
appropriate place on the PCB.
- This diode is polarized.
D1
- Orient the diode to match the black
line on the diode to the line drawn
on the PCB.
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Step 5: D1
- Mount and solder D1 into the
appropriate place on the PCB.
- This diode is polarized.
D1
- Orient the diode to match the black
line on the diode to the line drawn
on the PCB.
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Step 5: D1 (before)
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Step 5: D1 (after)
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Step 5: D1 (after close up)
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Step 6: R1 R2 R3
- Mount and solder R1, R2, and R3
into the appropriate place on the
PCB.
= R1 (YRO)
- These resistors are not polarized, so
orientation will not effect
performance.
= R2 (BrGrO)
- If you haven't already, bend the
leads of the resistor around the
provided plastic tool.
= R3 (GrBlR)
- This prevents stress fractures from
sharp angle bending.
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Step 6: R1 R2 R3 (before)
D1
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Step 6: R1 R2 R3 (after)
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Step 7: T1 CAUTION!!!
- Locate T1 (a four pronged
transformer) among your parts.
- This component is extremely fragile
composed of very small gauge wire
twined around a few nodes. The
wires are surrounded by brittle
plastic connected to four pins.
- If excess force is applied to these
metal pins the plastic will break
and sever the small wiring within
the transformer.
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Step 7: T1 CAUTION!!!
- Use CAUTION! The transformer
will fit into the PCB in one
orientation only.
D1
- **The transformer may not fit
perfectly. Try a dry fit at first to
note which leads may need
bending.
- If a lead does need bending use care
to slowly and gently bend the leads
with the plastic tool or a pair of
needle nose pliers.
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Step 7: T1 CAUTION!!!
- If you do force the transformer to
be flush with the PCB it WILL
break and render the kit useless.
T1
- Mount and solder T1 to the PCB.
- Match the dot on the transformer
to the dot on the PCB.
Example of flushness to board of T1
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Step 7: T1 (before)
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Step 7: T1 (after)
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Step 7: T1 (after close-up)
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Step 7: T1 (after close-up)
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Step 8: D2 D3
- Find D2 and D3 in the parts.
D2=D3
- Orient the diodes to match the grey
line with the line indicated on the
PCB.
- These diodes are polar, mount and
solder these diodes in their
appropriate places on the PCB.
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Step 8: D2 D3 (before)
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Step 8: D2 D3 (after)
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Step 9: C3 C4 C5
- Find C3 C4 and C5 in the provided
parts.
- There are two unpolarized
capacitors and one polarized
capacitor in this step.
C4=C5
- C3 is a polarized capacitor.
- C4=C5 are not polarized ceramic
capacitors so their orientation does
not matter.
C3
+
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Step 9: C3 (polar capacitor)
“107”
“L”
Positive lead
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Step 9: C3 C4 C5 (before)
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Step 9: C3 C4 C5 (after)
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Step 9: C3 C4 C5 (after close-up)
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Step 10: Q1
- Find Q1 (IRF830) in the provided
parts.
- This transistor must be bent over to
lay flat on the board.
- Mount the transistor such that it
can be bent and lay flat on the
PCB.
- Now solder the transistor in place.
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Step 10: Q1 (before)
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Step 10: Q1 (bending)
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Step 10: Q1 (after)
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Step 11: Q3
- Find Q3 (7805 Regulator) in the
provided parts.
Q3
- This transistor must be bent over to
lay flat on the board.
- Mount the transistor such that it
can be bent and lay flat on the
PCB.
- Now solder the transistor in place.
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Step 11: Q3 (before)
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Step 11: Q3 (bending)
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Step 11: Q3 (after)
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Step 12: C10
- Find C10 in the provided parts.
- C10 is a polarized capacitor.
C10
+
- Mount and solder this to the
appropriate location on the PCB.
- Note the positive hole displayed on
the PCB.
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Step 12: C10 (polar capacitor)
“107”
“L” Positive lead
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Step 12: C10 (before)
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Step 12: C10 (after)
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Step 13: D9 and Power Bridge
- Find D9 in the provided parts.
- D9 is a polarized diode.
D9
- Mount and solder this to the
appropriate location on the PCB.
- **Save a clipping of one of these
leads for the power bridge.
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Step 13: D9 and Power Bridge
- Bridge the left and middle holes of
the power section on the PCB as
shown using the lead clipping you
saved.
- Solder the bridge in place. This
removes the need for a bulky switch.
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Step 13: D9 and Power Bridge (before)
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Step 13: D9 and Power Bridge (after)
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Step 13: D9 and Power Bridge (close-up)
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Step 14:
Battery
Wiring
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Step 14: Battery Wiring
- Find the Geiger counter
wiring in the provided
parts (red, black and
blue).
- Solder the red wire to the
V+ location on the PCB.
- Solder the black wire to
the dot GND location on
the PCB.
- Leave the blue wire free
for later installation.
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Step 14: Battery Wiring (before)
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Step 14: Battery Wiring (after)
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Step 14: Battery Wiring (after)
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Step 14: Battery Wiring (after close-up)
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Step 15: 16 pin 4049 chip
- Find the 16 pin 4049 chip (U1) in the
provided parts.
- Orient the dot toward the notch as
shown in the following pictures.
U1
- Match notch to notch on the chip
and socket.
- Either method will work.
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Step 15: 16 pin 4049 chip
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Inspection
and High
Voltage (HV)
Test
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Step 16: HV Test 1st Powered Check
- Find one 9V test battery and
connect it to one of the two
9V connectors provided.
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Step 16: HV Test 1st Powered Check
- Connect power to the circuit
using the header and two pin
adapter provided.
- Be sure to match the wires of
the three pin Geiger header
to the correct power and
ground wires on the battery
wires as shown.
- *note red matches red and
black matches black.
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Step 16: HV Test 1st Powered Check
- Locate the provided
voltmeter and set the gauge
to read the maximum DC
voltage.
- Touch the red (positive) lead
to the junction of C4 and D2.
- Touch the black (negative)
lead to the negative terminal
of the 9V battery.
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Step 16: HV Test 1st Powered Check
- The voltmeter should read
between 800-550 Volts
depending on component
tolerances.
- If it does, remove power and
prepare for the next step in a
few moments.
- If not; check the orientation
of the diodes on the board,
continuity of soldering joints,
and raise your hand.
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Step 17: D4 D5 D6
- Locate D4, D5, and D6 in the
provided parts.
D4
- Match the black line to the
line on the PCB as shown.
- Mount and solder these
diodes in their required
locations on the PCB.
- **When bending make note
of the wider spacing of the
holes for mounting these
diodes.**
D5=D6
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Step 17: D4 D5 D6 (before)
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Step 17: D4 D5 D6 (after)
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Step 17: D4 D5 D6 (after close-up)
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Step 18: HV Test 2nd Powered Check
- Locate the provided
voltmeter and set the gauge
to read the maximum DC
voltage.
- Find a 9V battery and apply
power to the circuit.
- Touch the red (positive) lead
to the junction of C4 and D2.
- Touch the black (negative)
lead to the negative terminal
of the 9V battery.
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Step 18: HV Test 2nd Powered Check
- The voltmeter should read
500 Volts with little deviation
depending on component
tolerances and battery
charge.
- If it does, remove power and
prepare for the next step in a
few moments.
- If not check the orientation
of D4-D6 and raise your
hand.
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Step 19: C6 C7 C8
- Locate C6, C7, and C8 in the
provided parts.
- Some kits may have C7 as a orange
ceramic capacitor.
- Don’t worry both capacitors are the
same value, and interchangeable.
C6
C7
C8
- These capacitors are not polarized.
- Mount and solder these capacitors
to the appropriate location on the
PCB.
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Step 19: C6 C7 C8 (after)
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Step 19: C6 C7 C8 (after close-up)
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Step 20: C12 C13
- Locate C12 and C13 in the
provided parts.
- C12 is not a polar capacitor.
- C13 is not a polar capacitor
although the PCB may
indicate otherwise.
C13
C12
- Mount and solder these
capacitors to the appropriate
location on the PCB.
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Step 20: C12 C13 (before)
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Step 20: C12 C13 (after)
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Step 20: C12 C13 (after close-up)
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Step 21: R4 R5 R13
- Locate R4, R5, and R13 in
the provided parts.
= R4 (YVY)
- Mount and solder these
resistors to the appropriate
location on the PCB.
= R5 (BrBkBl)
= R13 (BrBkBl)
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Step 21: R4 R5 R13 (before)
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Step 21: R4 R5 R13 (after)
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Step 21: R4 R5 R13 (after close-up)
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Step 22: Q2
- Locate Q2 (small 3 pin
transistor) in the provided
parts.
- Mount and solder this
transistor to the appropriate
location on the PCB.
Q2
- Note the flat side of the
transistor should match the
drawing on the PCB when
mounted.
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Step 22: Q2 (before)
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Step 22: Q2 (after)
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Step 22: Q2 (after close-up)
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Step 23: 8 pin socket
- Locate the 8 pin socket
among the provided parts.
- Mount and solder this socket
to the appropriate location
on the PCB.
- Make sure it is flush with the
board, and tack down the
corners in the same manner
to ease the soldering process.
8-pin socket
with notch
to top
- Note the notch should match
the notch drawn on the PCB.
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Step 23: 8 pin socket (before)
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Step 23: 8 pin socket (after)
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Step 24: R7 R8 R9 R10
- Locate R7, R8, R9, and R10
among the provided parts.
= R7 (YVO)
- Mount and solder these
resistors to the appropriate
locations on the PCB.
= R8 (YVBr)
= R9 (OOBr)
= R10 (BrBkGr)
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Step 24: R7 R8 R9 R10 (before)
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Step 24: R7 R8 R9 R10 (after)
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Step 24: R7 R8 R9 R10 (after close up)
R8
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Step 25: D7-Red Led
- Locate D7 among the
provided parts.
- Mount and solder this diode
to the appropriate locations
on the PCB.
- Note the polarity of the
diode: The longer lead is
positive, the flat side is
negative, the flag points to
positive.
- All of these visual cues can
be used.
-
+
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Step 25: D7-Red Led (before)
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Step 25: D7-Red Led (after)
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Step 25: D7-Red Led (after close-up)
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Step 25: D7-Red Led (after close-up)
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Step 26: 555 Timer
- Locate U2 (555 Timer)
among the provided parts.
555 timer (U2)
- Mount this 8 pin chip to the
appropriate 8 pin socket on
the PCB.
- Note the dot on the chip and
mount as shown in the
following pictures.
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Step 26: 555 Timer (before)
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Step 26: 555 Timer (after)
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Step 26: 555 Timer (after close-up)
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Step 27: Audio Bridge
- Find two scraps of leads to
bridge two locations in the
same manner used in the
power bridge.
- Bridge and solder into place
a wire across the two
leftmost holes in the Audio
section.
Audio Bridge
Headphone Bridge
- Bridge and solder into place
a wire across the top two
holes in the Headphone
section.
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Step 27: Audio Bridge (before)
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Step 27: Audio Bridge (after)
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Step 28: Speaker
- Find the speaker in the
provided parts.
- It is polar note the polarity
on the part and the PCB.
- Mount and solder the
speaker in the appropriate
location on the PCB.
Speaker
- Now remove the seal over the
speaker.
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Step 28: Speaker (before)
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Step 28: Speaker (after)
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Step 29: Geiger Mueller (GM) Tube
- Find the GM Tube in the
provided parts.
+
- It is polar note the polarity
on the part and the PCB.
- On the tube the thin wire is
GM negative and the large
wire is GM positive.
-
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Step 29: Why is there epoxy on the end of the tube?!
- The tube is filled with an inert
gas to promote ionization in the
presence of radiation.
- The tube also has a very fragile
thin mica window to allow alpha
particles to pass through.
- This window will blow out in low
pressure environments.
- Don’t worry, this won’t
- The epoxy prevents blowout, but impact the merit of the kit
as the skin of the rocket
also eliminates some alpha
will block most alpha
particles from detection.
radiation.
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Step 29: GM Tube (Precautions)
- Do not overheat the GM tube
when soldering it can
overheat easily.
- Avoid the glass fill knob at
the rear of the tube. Shatter
this, and your tube won’t
work.
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Step 30: GM Tube-Positive Wire
- Find and strip ¼ inch from
each end of Red wire.
- Solder one of the striped
edges to the positive end of
the GM tube as shown.
- Be CAREFUL! Don’t let the
iron linger longer than 5
seconds before giving the
tube 10-15 seconds to cool.
- On the tube the thin wire is
GM negative and the large
wire is GM positive.
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Step 30: GM Tube-PCB Wiring
- Orient the tube on the bottom
of the board.
- Solder the free end of the red
wire into GM+ coming from
the bottom of the board up
through the hole.
- Solder the thin wire through
the GM – hole in the same
manner.
- Be CAREFUL! The thin
wire is frail and will snap if
bent too much.
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Step 30: GM Tube-PCB Wiring
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Step 30: GM Tube-PCB Wiring (before)
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Step 30: GM Tube-PCB Wiring (close-up)
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Step 30: GM Tube-PCB Wiring (close-up)
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Step 31: GM Tube-PCB Mounting
- Find the small piece of red mounting
wiring.
- It is not pre-cut and must be trimmed
as desired.
- Strip both ends of the red wiring and
solder through two holes on the
mounting array.
- ENSURE the insulation is on the wire
such that it will not conduct the energy
of the GM Tube.
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Step 31: GM Tube-PCB Mounting (before)
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Step 31: GM Tube-PCB Mounting (after)
TOP
BOTTOM
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Step 32: GM Tube-PCB Lacing
- Find the thin yellow wiring in the
provided parts.
- We will use this wire like shoelaces for
the mounting array on the GM PCB.
- Run the yellow wire through the first
two holes for each end as shown.
- The loose ends of the yellow wire
should extend upward through the
board.
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Step 32: GM Tube-PCB Lacing
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Step 32: GM Tube-PCB Lacing
- Begin a cross hatch method above and
below the board as if you are lacing a
shoe.
- When you get to the end, loop back
following a similar pattern until about
6 inches of yellow wire remains.
- We will tie off the wire in the middle of
the mounting array, so keep this in
mind.
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Step 32: GM Tube-PCB Lacing
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Step 32: GM Tube-PCB Lacing
- Tie a double
square knot
when the lacing
of the GM tube
is complete.
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Step 33: Data wire
- Strip the remaining
end of the blue data
wire and solder it in
place it to the
topmost pin of digital
out.
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Step 33: Data wire
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Final Product
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Final Product
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Smoke
Detector
Modification
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Overview:
- The Geiger counter that you assembled can detect all
three types of radiation: alpha, beta, and gamma.
- To test the Geiger counter, we will obtain a radioactive
source from the common household smoke detector.
- The common household smoke detector uses a very small
amount of Americium 241 to detect smoke particles in
the air.
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Safety:
- According to the World Nuclear Association [1],
Americium 241 is an alpha emitter that also emits some
low energy gamma rays.
- “Even swallowing the radioactive material from a smoke
detector would not lead to significant internal absorption
of Am-241, since the dioxide is insoluble.” [1]
- Caution: Although the sample is rather benign, do take
caution to keep it away from your face at all times.
- Caution: Also make sure that you wash your hands
before eating if you handle the sample.
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Let’s Begin!
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Step 1: Opening the detector housing
Opening the detector
housing and remove the lid.
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Step 1: Opening the detector housing
Opening the detector
housing and remove the lid.
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Step 2: Visually inspect the detector
Speaker
Radiation
Source
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Step 3: Peel back the Black cover over the Detector
Peel Back and
remove
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Step 3: Peel back the Black cover over the Detector
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Step 4: Remove PCB
Remove the PCB from
the protective housing
by bending the four
plastic prongs to release
and pulling the PCB.
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Step 4: Remove PCB
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Step 4: Remove PCB
The PCB is glued to
a middle prong.
Pull until it releases
from this prong,
which may require a
little additional
force.
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Step 5: Remove Radiation Source
Note the two metal
notches holding the
radiation source to
the PCB.
Bend these with a
provided
screwdriver as
shown so the source
will slide out of the
PCB.
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Step 5: Remove Radiation Source
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Step 6: Clipping attachments
Clip the attachments
on the radiation
source with the pliers
until the source is
free.
Use brute force to
extract the source,
and don’t worry
about damaging the
remainder of the
detector as it is not
needed.
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Step 6: Clipping attachments
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Step 6: Clipping attachments
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Step 6: Clipping attachments
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Step 7: The source is ready
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Final
Product:
Testing
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Final Product Testing
- Attach power to the circuit again.
- The Geiger counter should randomly blink
detecting usually 12-14 counts per minute
depending on sources in the area and
shielding.
- Acquire the provided alpha particle source
(taken from a smoke detector).
- Notice a large jump in the frequency of
counts.
- Each count represents the detection of a
radioactive particle by the Geiger counter.
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Final Product Testing
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Coronal
Discharge
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Coronal Discharge: An Overview
- Coronal discharge occurs in low pressure
environments with high voltages present.
- The air around a high potential (high
voltage) will become a conductor and emit a
bluish glow (plasma).
- This plasma will cause adverse effects for
the component as well as neighboring parts.
- The plasma is a bluish-purple and is visible
under normal lighting. (see images)
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Coronal Discharge: An Example
RockOn! Geiger counter seen through a vacuum chamber.
Area of
interest
near back
of D4-D6
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Coronal Discharge: An Example
Geiger counter seen through a vacuum chamber
Glow of
coronal
discharge
Close-up
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Coronal Discharge: The solution
- Coronal discharge is detrimental to parts.
- Dangerous to other payloads on the rocket.
- To mitigate these risks, we will add conformal coating to
the board to prevent coronal discharge.
- **Note: We will be in a pressurized environment on this
flight so this is not necessary, but is a good practice
especially with space applications.
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Conformal
Coating
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Step 1: Board Prep
- Take the board to a well
ventilated area (we will be
outside).
- Put on safety glasses and
rubber gloves.
- Place the board face up on
the prepared protected
surface.
- Shake the bottle lightly and
open it.
- MAKE SURE there is no
power on the board.
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Step 1: Board Prep
HV Section
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Step 2: Begin Coating
- Dip the brush in and begin
application coating the entire top
side of the board with an even
layer.
- Re-dipping the brush every 2-3
strokes is recommended.
- The board should look glossy
under lighting where coating has
been applied.
- If any safety concerns occur
consult the MSDS provided.
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Step 3: Detail Coating (chips in sockets)
- Coat the chips as well as long as
they are secured in their sockets.
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Step 3: Detail Coating (underneath components)
Apply
underneath
closely
oriented parts
like diodes,
capacitors,
and resistors
in this
manner.
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Step 4: Detail Coating (between components)
Apply
between
closely
oriented
parts
Use
smooth
strokes
(about 3
per dip)
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Step 5: Backside Coating
- Flip the board
over using
minimal contact
with the currently
curing coating.
- Coat the entire
backside as
desired using the
same 3 stroke per
dip rule.
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Step 5: Backside Coating
Apply across
the whole
board, make
sure the whole
PCB is coated
thoroughly.
Note glossy
look of
coated
board.
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Step 6: Touch-ups
- Visually inspect the board to ensure it
is coated thoroughly.
HV Section
- Make any touch-ups as necessary,
ensuring there are no bubbles
underneath parts.
- You may add additional coating to the
HV section if you desire, but one coat
is enough to do the job.
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Step 7: Drying and Clamping
- Flip the
board over
and attach
to helping
hands
where
shown.
- This area is
not HV and
won’t affect
the cure if
clamped
here
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Step 7: Drying and Clamping
- Allow the board to cure in a controlled environment for
24 hrs to achieve a full cure.
- Tack free cure is about 10 min. The coating wont stick
to your hand as readily after this stage.
- Handling cure is about 4-6 hrs depending on the
humidity.
- Cure time can be decreased by using a convection
heater at low heat (100 °F) and low humidity.
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